keys是什么意思？

That's the vision of a hotel chain that plans to send digital keys to guests' phones via an app instead of making them check in and get the traditional plastic swipe cards.

It turns out that the less skilled pianist spends more time looking at her fingers than does the expert who, in contrast, is more likely to be looking at the sheet music, or looking ahead at keys he's not yet playing.

They have to give so much thought and attention to the low-level mechanics of handling the ball, or fingering the keys or reading the music, that they are unable to give any thought to the thing that matters—the game, or the music, respectively.